U.S. patent application number 10/482362 was filed with the patent office on 2004-12-02 for defibrillator system.
Invention is credited to Gorny, Shraga, Katz, Iony, Mendelbaum, Mendel, Weiss, Teddy.
Application Number | 20040243185 10/482362 |
Document ID | / |
Family ID | 11075576 |
Filed Date | 2004-12-02 |
United States Patent
Application |
20040243185 |
Kind Code |
A1 |
Weiss, Teddy ; et
al. |
December 2, 2004 |
Defibrillator system
Abstract
The invention provides a portable defibrillation system (2),
including: a high voltage switch, and current control circuit (16)
connectable to and fed by a power source (6); a high voltage
transformer (14) fed by the current control circuit; a pair of
electrode pads (12, 12') connected to the high voltage transformer,
and a computer-based controller (18), operationally connected to
the current control circuit, for governing the application of
current to the high voltage transformer and, in turn, to the
electrodes, wherein the high voltage applied to a patient by means
of the electrode pads is directly derived from the power
source.
Inventors: |
Weiss, Teddy; (Jerusalem,
IL) ; Mendelbaum, Mendel; (Jerusalem, IL) ;
Gorny, Shraga; (Jerusalem, IL) ; Katz, Iony;
(Jerusalem, IL) |
Correspondence
Address: |
SUGHRUE MION, PLLC
2100 PENNSYLVANIA AVENUE, N.W.
SUITE 800
WASHINGTON
DC
20037
US
|
Family ID: |
11075576 |
Appl. No.: |
10/482362 |
Filed: |
July 20, 2004 |
PCT Filed: |
June 30, 2002 |
PCT NO: |
PCT/IL02/00533 |
Current U.S.
Class: |
607/5 |
Current CPC
Class: |
A61N 1/3912 20130101;
A61N 1/3906 20130101 |
Class at
Publication: |
607/005 |
International
Class: |
A61N 001/39 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 3, 2001 |
IL |
144120 |
Claims
What is claimed is:
1. A portable defibrillation system, comprising: a high voltage
switch and current control circuit connectable to and fed by a
power source; a high voltage transformer fed by said current
control circuit; a pair of electrode pads connected to said high
voltage transformer, and a computer-based controller, operationally
connected to said current control circuit, for governing the
application of current to said high voltage transformer and, in
turn, to said electrodes; wherein the high voltage applied to a
patient by means of said electrode pads is directly derived from
said power source.
2. The portable defibrillation system as claimed in claim 1,
further comprising measurement leads connecting said electrodes
with said computer-based controller.
3. The portable defibrillation system as claimed in claim 1,
wherein said power source is selected from the group consisting of
a mains AC power outlet and a battery-operated DC to AC
converter.
4. The portable defibrillation system as claimed in claim 1,
further comprising an audio-visual alarm connected to said
computer-based controller.
5. The portable defibrillation system as claimed in claim 1,
further comprising an ECG visual output manual operation connected
to said computer.
6. The portable defibrillation system as claimed in claim 1,
wherein said computer-based controller is connected to said power
source via a zero crossing detector for establishing a system
operation reference.
7. The portable defibrillation system as claimed in claim 6,
further comprising a main gate synchronizer connected to said zero
crossing detector and a patient's ECG signal.
8. The portable defibrillation system as claimed in claim 1,
further comprising a wave shaper for shaping voltage pulses
produced by said high voltage transformer.
9. The portable defibrillation system as claimed in claim 8,
wherein said wave shaper is capable of application of pulses with a
variable peak output voltage facilitating delivery of an exact
amount of energy required.
10. The portable defibrillation system as claimed in claim 1,
further comprising an exponential amplitude controller connected in
circuit between said power source and said high voltage
transformer.
Description
FIELD OF THE INVENTION
[0001] The present invention relates to intensive care systems for
the early treatment of sudden arrhythmias, and more particularly,
to such systems which are suitable for domestic or outpatient use
by non-medical personnel, on a dying patient.
BACKGROUND OF THE INVENTION
[0002] Heretofore, sudden cardiac death caused by ventricular
fibrillation or cardiac arrest, was the major cause of death among
the adult population in developed countries. Ventricular
fibrillation can be halted and normal heart activity restored, by
the electrical defibrillation procedure, comprising an electric
shock applied to the heart. Similarly, heart arrest can be treated
by pacing electrical signals, that is, a pulse train, at the rate
of 60-80 pulses per minute. The defibrillation procedure is usually
effective when applied in intensive care units in hospitals, where
a state of fibrillation is easily detected and treatment is quickly
applied. Hospital intensive care units are usually equipped with
expensive defibrillation equipment, along with professional
personnel who are able to perform the treatment.
[0003] The above considerations also apply to the state of heart
arrest and the use of an external pacemaker device. Thus, while the
description of the present invention relates to defibrillators, it
should be understood that it is also meant to include pacemaker
systems.
[0004] It is of paramount importance that a defibrillation
procedure be done immediately; otherwise, irreversible, irreparable
damage is caused. The patient's brain is be damaged within minutes
of the start of fibrillation, due to a lack of oxygen supply, and
all other organs will stop functioning. Early defibrillation
restores cardiac function and spontaneous respiration, avoiding
anoxic brain damage. In addition, there is a clear linkage between
the elapsed time between the beginning of ventricular fibrillation,
the beginning of the defibrillation procedure, and the procedure's
success.
[0005] The majority of potential fibrillation victims live at home,
however, and are not under constant medical supervision. This is
even more so with the modern trend towards treatment of patients at
home. These people cannot be given immediate defibrillation
treatment, for several reasons:
[0006] 1) From the moment that the victim of ventricular
fibrillation loses consciousness, it will take at least from 10-20
minutes until the mobile care unit reaches him. Therefore, in such
cases defibrillation is usually not successful and irreversible
cardiac damage is caused; if the patient survives, he will remain
in coma with permanent brain damage.
[0007] 2) Presently used defibrillation equipment is expensive,
costing in the range of thousands of dollars. The majority of the
people cannot afford to include such equipment as part of their
home first aid kits.
[0008] 3) Much of the presently used defibrillation equipment must
be operated by professional, trained medical personnel, who
diagnose the case as fibrillation, find the right equipment, and
use it correctly to apply electric shock at the proper location.
Non-professional people are unfamiliar with such equipment; and
moreover, they tend to panic and be ineffective in an emergency
situation. Therefore, family members and neighbors usually cannot
be relied upon to perform defibrillation treatment.
[0009] 4) The defibrillation equipment has to be kept in good
operating condition so that it will be ready for use in an
emergency. Hospital maintenance teams routinely keep all equipment
in good condition and perform required periodical tests and
repairs. It is difficult, however, to keep complex defibrillation
equipment in good condition at home and to do the required testing
and repairs.
[0010] 5) Defibrillation equipment may be dangerous if misused.
High voltages generated by the equipment can endanger its
operators, children, or other non-professionals. The existing
equipment lacks the safety devices which are required for home
use.
SUMMARY OF THE INVENTION
[0011] It is therefore an object of the present invention to
overcome the above-mentioned problems and to provide a low-cost,
automatic defibrillation system utilizing available alternating
current, for treating fibrillation and cardiac arrest patients at
home.
[0012] Thus, the invention provides a portable defibrillation
system, comprising a high voltage switch and current control
circuit connectable to and fed by a power source; a high voltage
transformer fed by said current control circuit; a pair of
electrode pads connected to the high voltage transformer, and a
computer-based controller, operationally connected to the current
control circuit, for governing the application of current to the
high voltage transformer and, in turn, to the electrodes, wherein
the high voltage applied to a patient by means of the electrode
pads is directly derived from the power source.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] The invention will now be described in connection with
certain preferred embodiments with reference to the following
illustrative figures so that it may be more fully understood.
[0014] With specific reference now to the figures in detail, it is
stressed that the particulars shown are by way of example and for
purposes of illustrative discussion of the preferred embodiments of
the present invention only, and are presented in the cause of
providing what is believed to be the most useful and readily
understood description of the principles and conceptual aspects of
the invention. In this regard, no attempt is made to show
structural details of the invention in more detail than is
necessary for a fundamental understanding of the invention, the
description taken with the drawings making apparent to those
skilled in the art how the several forms of the invention may be
embodied in practice.
[0015] In the drawings:
[0016] FIG. 1 is a block diagram of the defibrillation system
according to the present invention;
[0017] FIG. 2 is a circuit diagram of a first embodiment of the
invention;
[0018] FIG. 3 depicts graphs showing the waveforms produced at
different points in the circuit of FIG. 2;
[0019] FIG. 4 is a circuit diagram of a second embodiment of the
invention;
[0020] FIG. 5 depicts graphs showing the waveforms produced at
different points in the circuit of FIG. 4;
[0021] FIG. 6 is a circuit diagram of another embodiment of the
invention, and
[0022] FIG. 7 depicts graphs showing the waveforms produced at
different points in the circuit of FIG. 6.
DETAILED DESCRIPTION
[0023] Referring now to FIG. 1, there is shown a block diagram of
an automatic defibrillation system 2 according to the present
invention. System 2 is connectable, via switch 4, to a common power
source 6, e.g., AC mains outlet 8 or, alternatively, to a
battery-operated DC-to-AC converter 10, for use when mains power is
not available.
[0024] System 2 includes a pair of electrodes 12, 12' electrically
connected to, and fed by, a high voltage output transformer 14,
e.g., a step-up transformer, receiving power from source 6 via a
high voltage switch and current control circuit 16. The latter is
governed by computer-based controller 18. Advantageously,
measurement leads 19, 19' connect electrodes 12, 12' to the
computer-based controller 18. The system may be optionally
furnished with an audio-visual alarm 20 and an ECG visual output
manual operation unit 22.
[0025] FIG. 2 illustrates a first embodiment of the invention.
System 2 is connectable via switch 4 to the mains power source 6. A
step-down transformer 24 feeds a power supply 26, providing the
required DC voltage to the system. A zero cross detector 28 is
connected to the low-voltage side of transformer 24, and detects
the exact timing of the zero crossing of the mains sine wave, to be
used as a reference for the operation of the system. A monostable
30, e.g., a 30 msec monostable, is either manually triggered by
push button 32 or automatically through leads 34 to a computer (not
shown) for analyzing the ECG signals of a patient. The computer is
connected to a main gate synchronizer 36, which synchronizes
between the input signals arriving from the zero crossing detector
28 and the signals arriving from the monostable 30. The output from
main gate synchronizer 36 is fed to a positive half-cycle detector
38, for detecting the beginning of a first positive half-cycle of
the mains occurring in response to manual or automatic
triggering.
[0026] As a first part of the procedure for controlling the power
that will be transferred through the output transformer 14 to the
electrodes 12, 12', circuit 40 enables a time delay of, e.g., 0 to
5 msec, counted from the zero crossing of the sine wave. This delay
marks the beginning of the pulse of energy transferred to the
patient. The second part of the power-controlling procedure
comprises generating a pulse in generator 42, e.g., 1 to 10 msec
wide, according to the amount of energy that has to be transferred
to transformer 14 and thence, via electrodes 12, 12', to the
patient.
[0027] The high voltage switch and current control 16 can be
divided into two components: IGBT control 16', which transforms the
logic levels used in the other parts of the system to the levels
required to trigger the high current IGBT switch 16". The latter is
a high power switch supplying the primary of high voltage
transformer 14 with an adequate waveform, shaped by pulse width
generator 42.
[0028] Referring now also to FIG. 3, the system's waveforms are
shown in alignment, including the mains waveform A, the zero cross
output signal B, monostable 30 output signal C, main gate 36
synchronizing signal D, first positive half-cycle signal E, delay
signal F, pulse width waveform G at the output of the pulse width
generator 42, and the actual high voltage output waveform H, which
is applied to electrodes 12, 12'.
[0029] Thus, from the synchronized signal, the zero crossing pulse
preceding the first positive half-cycle is selected and used as a
triggering signal for the generation of a pulse whose beginning
timing and end timing can be controlled in order to ensure that the
required amount of energy is transferred to the patient. This pulse
is, in turn, used as a gating signal to the high current switch
applying the mains' power to the step-up output transformer 14,
used to obtain the required high voltage to be applied to the
patient's chest.
[0030] FIGS. 4 and 5 depict a modification of the embodiment of
FIGS. 2 and 3, in which there is provided a high frequency
generator 44 for providing a train of high frequency (A, FIG. 5),
e.g., a 12 to 24 KHz sinusoidal waveform B, to be used as a power
source for the step-up output transformer 14. After passing through
a wave shaper 46, the pulses are shaped as shown at H. The high
voltage output applied to the patient is thus shown as I of FIG. 5.
The wave shaper 46 enables the application of consecutive pulses
shaped according to the requirements within limits of less than 200
ms delay, in contrast with known systems based on capacitor
discharge where it takes several seconds before a second discharge
is possible.
[0031] Furthermore, the wave shaper enables the application of
pulses shaped according to any requirements, within limits of the
sine wave, having variable peak outputs and starting and stopping
at will, creating a mono or biphasic waveform, or continuous wave
composed of two or more segments, thereby enabling the delivery of
the exact amount of energy required.
[0032] A further embodiment is shown in FIGS. 6 and 7. Accordingly,
an exponential amplitude controller 48 is connected in circuit
between the mains and the output transformer 14. The controller 48
is used to control the amplitude (A, FIG. 7) of the sinusoidal
waveform obtained by the mains (B, FIG. 7), resulting in a
progressively reduced high voltage waveform C. Amplitude decrease
is calculated by the system in such a way that the accumulated
energy transferred to the patient reaches the required value
determined by the patient's condition and other, per se known,
considerations.
[0033] It will be evident to those skilled in the art that the
invention is not limited to the details of the foregoing
illustrated embodiments and that the present invention may be
embodied in other specific forms without departing from the spirit
or essential attributes thereof. The present embodiments are
therefore to be considered in all respects as illustrative and not
restrictive, the scope of the invention being indicated by the
appended claims rather than by the foregoing description, and all
changes which come within the meaning and range of equivalency of
the claims are therefore intended to be embraced therein.
* * * * *